CN114370013A - Variable-curvature clamping type anchorage device suitable for FRP (fiber reinforced plastic) plate and design method - Google Patents

Variable-curvature clamping type anchorage device suitable for FRP (fiber reinforced plastic) plate and design method Download PDF

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Publication number
CN114370013A
CN114370013A CN202210267288.3A CN202210267288A CN114370013A CN 114370013 A CN114370013 A CN 114370013A CN 202210267288 A CN202210267288 A CN 202210267288A CN 114370013 A CN114370013 A CN 114370013A
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plate
frp
clamping
variable
clamping plate
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刘晓刚
朵永玉
岳清瑞
王安妮
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University of Science and Technology Beijing USTB
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University of Science and Technology Beijing USTB
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    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D22/00—Methods or apparatus for repairing or strengthening existing bridges ; Methods or apparatus for dismantling bridges
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D19/00—Structural or constructional details of bridges
    • E01D19/14—Towers; Anchors ; Connection of cables to bridge parts; Saddle supports
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/08—Members specially adapted to be used in prestressed constructions
    • E04C5/12—Anchoring devices
    • E04C5/127—The tensile members being made of fiber reinforced plastics
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G23/00—Working measures on existing buildings
    • E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
    • E04G23/0218—Increasing or restoring the load-bearing capacity of building construction elements
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D2101/00—Material constitution of bridges
    • E01D2101/40—Plastics
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G23/00—Working measures on existing buildings
    • E04G23/02—Repairing, e.g. filling cracks; Restoring; Altering; Enlarging
    • E04G23/0218—Increasing or restoring the load-bearing capacity of building construction elements
    • E04G2023/0251—Increasing or restoring the load-bearing capacity of building construction elements by using fiber reinforced plastic elements

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • Reinforcement Elements For Buildings (AREA)

Abstract

The invention discloses a variable curvature clamping type anchorage device suitable for FRP plates and a design method thereof. Be applicable to individual layer FRP board ground tackle and press from both sides tightly between punch holder and lower plate and have individual layer FRP board, punch holder and lower plate all have the variable camber wave form, and the bending of FRP board becomes the variable camber wave form, and the variable camber wave form has adjustable wave form and crest. The anchor is suitable for a multilayer FRP plate anchor, and an upper ear plate, a lower ear plate and a clamping piece are added on the anchor of a single-layer FRP plate. The design method comprises the following steps: designing a variable curvature waveform function, and processing an upper clamping plate, a lower clamping plate and a clamping piece according to the variable curvature waveform function; installing a lower ear plate, a lower clamping plate, an FRP plate, a clamping piece, an upper clamping plate and an upper ear plate; and installing a gasket and a bolt, tightening a nut to apply variable pretightening force to the bolt, and bending the FRP plate into a variable-curvature waveform. The variable curvature clamping type anchorage device can effectively improve the stress distribution in the anchorage device, reduce the stress concentration of the loading end of the anchorage device, shorten the anchoring length and improve the anchoring efficiency.

Description

Variable-curvature clamping type anchorage device suitable for FRP (fiber reinforced plastic) plate and design method
Technical Field
The invention relates to the technical field of civil engineering and composite materials, in particular to a variable-curvature clamping type anchorage device suitable for an FRP plate and a design method.
Background
FRP (Fiber Reinforced Polymer) has the characteristics of light weight, high strength, corrosion resistance, excellent fatigue resistance and the like, and has been widely used for structural reinforcement or reinforcement and maintenance. However, FRP is an anisotropic material having low transverse compressive strength and shear strength (about 1/20-1/10 of longitudinal tensile strength), and is liable to cause failure of anchoring and premature failure, so that its high tensile strength characteristics cannot be fully exerted.
The FRP plates have the advantages of larger specific surface area, better bending performance, easier improvement of stress distribution by controlling the appearance of the anchorage device and the like, and are gradually used for bridge reinforcement, external prestress and spatial structure. However, the existing anchorage device suitable for the FRP plate can only anchor a single-layer or a small number of FRP plates, and is not suitable for anchoring a large-tonnage FRP plate cable. And the existing anchorage device has the problems of uneven stress distribution, longer anchoring length, complex manufacturing and installation and the like.
Disclosure of Invention
The invention provides a variable curvature clamping type anchorage device suitable for an FRP plate and a design method, the existing FRP plate clamping type anchorage device has the following problems that the existing FRP plate anchorage device can only anchor a single layer or a small number of layers of FRP plates and is not suitable for anchoring a large-tonnage FRP plate cable; the internal stress of the anchorage device is not uniformly distributed, the stress concentration exists at the loading end of the anchorage device, the anchoring length is longer, and the manufacture and installation are complicated.
To solve the above technical problem, an embodiment of the present invention provides the following solutions:
on one hand, the variable curvature clamping type anchorage device suitable for the FRP plate comprises an upper clamping plate and a lower clamping plate which are sequentially arranged, a single-layer FRP plate is clamped between the upper clamping plate and the lower clamping plate, both the upper clamping plate and the lower clamping plate are provided with variable curvature waveforms, the FRP plate is bent into the variable curvature waveforms, and the variable curvature waveforms are provided with adjustable waveforms and wave crests.
Preferably, the variable curvature clamping type anchor further comprises an upper lug plate, a lower lug plate and a variable curvature wave-shaped clamping piece, wherein a plurality of layers of clamping pieces are arranged between the upper clamping plate and the lower clamping plate, the clamping pieces have variable curvature waves, and FRP plates are clamped on each layer of a multi-layer member formed by the upper clamping plate, the plurality of layers of clamping pieces and the lower clamping plate.
Preferably, the variable curvature wave function of the upper clamping plate, the lower clamping plate and the clamping piece satisfies the following condition: the derivative is continuously conducted in the anchorage device, the first derivative and the second derivative are both 0 at the anchorage device outlet, and the first derivative is 0 at the anchorage device inlet.
Preferably, the upper clamping plate, the lower clamping plate, the clamping piece and the FRP plate have the same waveform in the anchorage device, the bending does not occur at the outlet of the anchorage device, the bending degree of each wave band is gradually increased along with the increase of the distance from the outlet of the anchorage device, and the wave bands are tangent to the longitudinal direction of the FRP plate at the inlet of the anchorage device.
Preferably, the function of the variable curvature waveform is:
Figure 411450DEST_PATH_IMAGE001
in the formula (I), the compound is shown in the specification,
Figure 689109DEST_PATH_IMAGE002
，
Figure 531164DEST_PATH_IMAGE003
is the distance from the coordinate center along the longitudinal direction of the FRP plate, and L is the anchoring length, then
Figure 988690DEST_PATH_IMAGE004
；
Figure 68641DEST_PATH_IMAGE005
As the abscissa
Figure 454885DEST_PATH_IMAGE006
The corresponding amplitude value; A. m, n and w are four main parameters for controlling the waveform, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3.
Preferably, the variable curvature clamping type anchor further comprises a gasket, a bolt and a nut, the bolt penetrates through the upper lug plate, the upper clamping plate, the clamping piece, the lower clamping plate and the lower lug plate, and the nut is screwed on the bolt.
Preferably, the upper lug plate, the upper clamping plate, the clamping piece, the lower clamping plate and the lower lug plate are all provided with bolt holes, and bolts penetrate through the bolt holes.
Preferably, the pretightening force applied to the bolt by the nut is gradually increased from the outlet of the anchor to the inlet of the anchor, and the pretightening force increase value of each stage is 10-20 kN.
Preferably, in the multiple layers of the FRP boards, the uppermost FRP board and the lowermost FRP board are respectively closely attached to the upper clamping plate and the lower clamping plate, and the intermediate FRP board is closely attached to the clamping plate.
In another aspect, an embodiment of the present invention provides a method for designing a variable curvature clamping anchor suitable for an FRP plate, where the method is used to design the variable curvature clamping anchor suitable for an FRP plate, and the method includes:
setting the outlet of the anchorage device as a coordinate center (0, 0), and designing the variable curvature waveform function, wherein the function is as follows:
Figure 580973DEST_PATH_IMAGE001
in the formula (I), the compound is shown in the specification,
Figure 45453DEST_PATH_IMAGE002
，
Figure 776648DEST_PATH_IMAGE003
is the distance from the coordinate center along the longitudinal direction of the FRP plate, and L is the anchoring length, then
Figure 802635DEST_PATH_IMAGE004
；
Figure 884861DEST_PATH_IMAGE005
As the abscissa
Figure 153031DEST_PATH_IMAGE006
The corresponding amplitude value; A. m, n and w are four main parameters for controlling waveforms, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3; obtaining the optimal parameter combination of A, m, n and w through parameter optimization analysis to obtain the variable curvature waveform;
processing an upper clamping plate, a lower clamping plate and a waveform clamping plate according to the variable curvature waveform function;
placing the lower clamping plate on the lower ear plate, gradually superposing a layer of FRP plate and a layer of clamping plate to a required number of layers, placing the upper clamping plate on the top FRP plate, and placing the upper ear plate on the upper clamping plate;
placing gaskets at bolt holes at the top of the upper ear plate and the bottom of the lower ear plate, wherein bolts sequentially penetrate through the gaskets, the upper ear plate, the upper clamping plate, the clamping pieces, the lower clamping plate and the lower ear plate;
and tightening the nut to apply variable pre-tightening force to the bolt, and bending the FRP plate into a variable-curvature waveform, so that the FRP plate is tightly clamped.
The scheme of the invention at least comprises the following beneficial effects:
in the scheme, the variable curvature clamping type anchorage device suitable for the FRP plate comprises an anchorage device suitable for a single-layer FRP plate and an anchorage device suitable for a multilayer FRP plate, the design method of the variable curvature clamping type anchorage device suitable for the FRP plate comprises a design method of the anchorage device suitable for the single-layer FRP plate and a design method of the anchorage device suitable for the multilayer FRP plate, the anchorage device suitable for the multilayer FRP plate is suitable for anchoring a large-tonnage FRP plate cable, and the upper clamping plate 6, the lower clamping plate 7, the clamping pieces 8 and the FRP plate 9 all have the same variable curvature waveform, so that the stress distribution in the anchorage device can be effectively improved, the stress concentration at a loading end of the anchorage device is reduced, the anchorage length is shortened, the anchorage efficiency is improved, and the advantage of high tensile strength of a material of the FRP plate 9 is fully exerted.
Drawings
FIG. 1 is a schematic structural view of a variable curvature clamping anchor suitable for FRP plates according to a first embodiment of the invention;
FIG. 2 is a schematic structural view of a variable curvature clamping anchor suitable for FRP plates according to a second embodiment of the invention;
FIG. 3 is a schematic structural view of an upper clamping plate of the variable curvature clamping type anchorage device for FRP plates according to the present invention;
FIG. 4 is a schematic view of the structure of the lower clamping plate of the variable curvature clamping type anchorage device for FRP plates according to the present invention;
FIG. 5 is a schematic view of the clamping piece of the variable curvature clamping type anchorage device for FRP plates according to the present invention;
FIG. 6 is a schematic view of the structure of a multi-layered FRP plate suitable for a variable curvature clamping anchor for FRP plates according to the present invention;
FIG. 7 is a flow chart of a method for designing a variable curvature clamping anchor suitable for FRP plates according to a third embodiment of the invention;
fig. 8 is a flowchart of a method for designing a variable-curvature clamping anchor suitable for an FRP panel according to a fourth embodiment of the present invention.
Reference numerals:
1. a gasket; 2. a bolt; 3. a nut; 4. an upper ear plate; 5. a lower ear plate; 6. an upper splint; 7. a lower splint; 8. a clip; 9. FRP plates; A. an anchor inlet; B. an anchor outlet.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Example one
As shown in fig. 1, 3 and 4, the present embodiment provides a variable curvature clamping type anchorage device suitable for a single-layer FRP plate, which includes an upper clamping plate 6 and a lower clamping plate 7 arranged in sequence, wherein a single-layer FRP plate 9 is clamped between the upper clamping plate 6 and the lower clamping plate 7, both the upper clamping plate 6 and the lower clamping plate 7 have variable curvature waveforms, and the FRP plate 9 is bent into the variable curvature waveforms, which have adjustable waveforms and wave crests. The variable curvature clamping type anchorage device of the embodiment is a single-layer FRP plate anchorage device, the upper clamping plate 6, the lower clamping plate 7 and the FRP plate 9 all have the same variable curvature waveform, stress distribution in the anchorage device can be effectively improved, stress concentration of a loading end of the anchorage device is reduced, anchoring length is shortened, anchoring efficiency is improved, and the advantage of high tensile strength of the FRP plate 9 is fully exerted.
Specifically, the function of the varying curvature waveform is:
Figure 941996DEST_PATH_IMAGE001
in the formula (I), the compound is shown in the specification,
Figure 434157DEST_PATH_IMAGE002
，
Figure 770722DEST_PATH_IMAGE003
is a distance from the coordinate center in the longitudinal direction of the FRP plate 9, and L is an anchoring length, then
Figure 373742DEST_PATH_IMAGE004
；
Figure 548371DEST_PATH_IMAGE005
As the abscissa
Figure 945855DEST_PATH_IMAGE006
The corresponding amplitude value; A. m, n and w are four main parameters for controlling the waveform, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3.
Specifically, the variable curvature wave functions of the upper and lower splints 6, 7 satisfy the following conditions: the first derivative and the second derivative are both 0 at the outlet B of the anchorage device, and the first derivative is 0 at the inlet A of the anchorage device. The continuous change of the curvature of the FRP plate 9 in the anchorage device enables the transverse compressive stress peak value to be transferred to the rear end of the anchorage device, and effectively avoids the compressive damage caused by the transverse compressive stress concentration at the exit B of the anchorage device. The upper clamping plate 6, the lower clamping plate 7 and the FRP plate 9 have the same waveform in the anchorage device, bending does not occur at the outlet B of the anchorage device, along with the increase of the distance from the outlet B of the anchorage device, the bending degree of each wave band is gradually increased, so that the longitudinal tensile stress of the FRP plate 9 is gradually reduced from the outlet B of the anchorage device to the inlet A of the anchorage device, and the longitudinal tensile stress is gradually increased from the outlet B of the anchorage device to the inlet A of the anchorage device, thereby not only avoiding the stress concentration at the outlet B of the anchorage device under the action of tensile and bending coupling, but also effectively reducing the anchoring length and improving the economic benefit.
Specifically, variable camber centre gripping formula ground tackle still includes gasket 1, bolt 2 and nut 3, and bolt 2 passes gasket 1, punch holder 6, lower plate 7, and nut 3 closes soon on bolt 2, and bolt 2 adopts high strength bolt 2, and nut 3 adopts locking nut 3 or high strength nut 3. And the upper clamping plate 6 and the lower clamping plate 7 are both provided with holes for bolts 2, and the bolts 2 penetrate through the holes for bolts 2. The pretightening force applied to the bolt 2 by the nut 3 is gradually increased from the anchor outlet B to the anchor inlet A, and the increase value of each pretightening force is 10-20 kN. The variable curvature clamping type anchorage device of the embodiment applies pre-tightening force with different sizes to bolts 2 at different positions by screwing the nut 3, so that the FRP plate 9 is bent and formed in the anchorage device and tightly attached to the clamping plate.
The FRP board 9 used in this embodiment is a unidirectional board, and may be a CFRP board 9, or a hybrid fiber board formed by mixing carbon fibers and other fibers. The FRP is in a napped state in the part within the anchoring length, and the surface is free of a resin layer.
Example two
As shown in fig. 2 to 6, on the basis of the first embodiment, the variable curvature clamping type anchor applicable to a multilayer FRP plate provided by this embodiment further includes an upper ear plate 4, a lower ear plate 5 and a variable curvature waveform clamping piece 8, the multilayer clamping piece 8 is disposed between the upper clamping plate 6 and the lower clamping plate 7, the clamping piece 8 has a variable curvature waveform, an FRP plate 9 is clamped on each layer of a multilayer member formed by the upper clamping plate 6, the multilayer clamping piece 8 and the lower clamping plate 7, so as to form a multilayer FRP plate 9, in the multilayer FRP plate 9, the uppermost layer FRP plate 9 and the lowermost FRP plate 9 are respectively tightly attached to the upper clamping plate 6 and the lower FRP plate 7, and the intermediate layer FRP plate 9 is tightly attached to the clamping piece 8. The variable curvature clamping type anchorage device is a multilayer FRP plate anchorage device and is suitable for anchoring a large-tonnage FRP plate cable. The upper clamping plate 6, the lower clamping plate 7, the clamping pieces 8 and the FRP plate 9 all have the same variable curvature waveform, so that the stress distribution in the anchorage device can be effectively improved, the stress concentration of a loading end of the anchorage device is reduced, the anchoring length is shortened, the anchoring efficiency is improved, and the advantage of high tensile strength of the FRP plate 9 is fully exerted.
Specifically, the variable curvature waveform function of the clip 8 satisfies the condition: the first derivative and the second derivative are both 0 at the outlet B of the anchorage device, and the first derivative is 0 at the inlet A of the anchorage device. The upper clamping plate 6, the lower clamping plate 7, the clamping pieces 8 and the FRP plate 9 have the same waveform in the anchorage device, the bending does not occur at the outlet B of the anchorage device, the bending degree of each wave band is gradually increased along with the increase of the distance from the outlet B of the anchorage device, and the wave bands are tangent to the longitudinal direction of the FRP plate 9 at the inlet A of the anchorage device.
Specifically, the variable curvature clamping type anchor further comprises a gasket 1, a bolt 2 and a nut 3, wherein the bolt 2 penetrates through the upper lug plate 4, the upper clamping plate 6, the clamping piece 8, the lower clamping plate 7 and the lower lug plate 5, and the nut 3 is screwed on the bolt 2. All be equipped with bolt 2 hole on upper ear plate 4, lower ear plate 5, the clamping piece 8, bolt 2 passes bolt 2 hole. The variable curvature clamping type anchorage device of the embodiment applies pre-tightening force with different sizes to bolts 2 at different positions by screwing the nut 3, so that the FRP plate 9 is bent and formed in the anchorage device and is tightly attached to the clamping piece 8 and the clamping plate.
Specifically, one end of the upper ear plate 4 and the lower ear plate 5 is in a semicircular structure, and is provided with a central hole concentric with the semicircular structure.
EXAMPLE III
As shown in fig. 7, the present embodiment provides a method for designing a variable curvature clamping anchor suitable for an FRP panel, where the method is used to design the variable curvature clamping anchor suitable for an FRP panel according to the first embodiment, and the method includes:
s110, setting the position of an anchor device outlet B as a coordinate center (0, 0), and designing a variable curvature waveform function, wherein the function is as follows:
Figure 972979DEST_PATH_IMAGE007
in the formula (I), the compound is shown in the specification,
Figure 379689DEST_PATH_IMAGE002
，
Figure 143246DEST_PATH_IMAGE003
is the distance from the coordinate center in the longitudinal direction of the FRP plate 9; l is the anchoring length, then
Figure 242789DEST_PATH_IMAGE004
；
Figure 459007DEST_PATH_IMAGE005
As the abscissa
Figure 872671DEST_PATH_IMAGE006
The corresponding amplitude value; A. m, n and w are four main parameters for controlling waveforms, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3; obtaining the optimal parameter combination of A, m, n and w through parameter optimization analysis to obtain a variable curvature waveform; wherein, different combinations of A, m, n and w can obtain different variable curvature waveforms. The optimal variable curvature wave function takes the principle of reducing the tensile stress peak value of the FRP plate 9 at the outlet B of the anchorage device, enabling the transverse compressive stress to be uniformly distributed and reducing the compressive stress peak value as a principle;
s120, processing the upper clamping plate 6 and the lower clamping plate 7 according to the variable curvature waveform function;
s130, placing the single-layer FRP plate 9 on the lower clamping plate 7, and placing the upper clamping plate 6 on the FRP plate 9;
s140, placing the gasket 1 at the hole of the bolt 2 at the top of the upper clamping plate 6 and the bottom of the lower clamping plate 7, and sequentially penetrating the bolt 2 through the gasket 1, the upper clamping plate 6 and the lower clamping plate 7;
s150, tightening the nut 3 to apply variable pre-tightening force to the bolt 2, and bending the FRP plate 9 into a variable-curvature waveform, so that the FRP plate 9 is tightly clamped.
The design method of the embodiment is a design method for designing a single-layer FRP plate anchorage, and the upper clamping plate 6, the lower clamping plate 7 and the FRP plate 9 all have the same variable curvature waveform, so that the stress distribution in the anchorage can be effectively improved, the stress concentration of a loading end of the anchorage is reduced, the anchoring length is shortened, the anchoring efficiency is improved, and the advantage of high tensile strength of the FRP plate 9 is fully exerted.
Example four
As shown in fig. 8, the present embodiment provides a method for designing a variable curvature clamping anchor suitable for an FRP panel, where the method is used to design a variable curvature clamping anchor suitable for an FRP panel as in the second embodiment, and the method includes:
the embodiment of the invention provides a variable-curvature clamping type anchorage device design method suitable for an FRP plate, which comprises the following steps:
s210, setting the position of an anchor device outlet B as a coordinate center (0, 0), and designing a variable curvature waveform function, wherein the function is as follows:
Figure 585674DEST_PATH_IMAGE001
in the formula (I), the compound is shown in the specification,
Figure 324960DEST_PATH_IMAGE002
，
Figure 90791DEST_PATH_IMAGE003
is the distance from the coordinate center in the longitudinal direction of the FRP plate 9; l is the anchoring length, then
Figure 776987DEST_PATH_IMAGE004
；
Figure 801619DEST_PATH_IMAGE005
As the abscissa
Figure 977386DEST_PATH_IMAGE006
The corresponding amplitude value; A. m, n and w are four main parameters for controlling waveforms, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3; obtained by parameter optimization analysisCombining the optimal parameters A, m, n and w to obtain a variable curvature waveform; wherein, different combinations of A, m, n and w can obtain different variable curvature waveforms. The optimal variable curvature wave function takes the principle of reducing the tensile stress peak value of the FRP plate 9 at the outlet B of the anchorage device, enabling the transverse compressive stress to be uniformly distributed and reducing the compressive stress peak value as a principle;
s220, processing the upper clamping plate 6, the lower clamping plate 7 and the waveform clamping plate 8 according to the variable curvature waveform function;
s230, placing the lower clamping plate 7 on the lower ear plate 5, gradually superposing the lower clamping plate 7 and the clamping plate 8 in sequence to the required number of layers, placing the upper clamping plate 6 on the uppermost FRP plate 9, and placing the upper ear plate 4 on the upper clamping plate 6;
s240, placing the gasket 1 at the positions of the holes of the bolts 2 at the top of the upper ear plate 4 and the bottom of the lower ear plate 5, wherein the bolts 2 sequentially penetrate through the gasket 1, the upper ear plate 4, the upper clamping plate 6, the clamping piece 8, the lower clamping plate 7 and the lower ear plate 5;
s250, tightening the nut 3 to apply variable pre-tightening force to the bolt 2, and bending the FRP plate 9 into a variable-curvature waveform, so that the FRP plate 9 is tightly clamped.
The design method of the embodiment is a design method for designing a multi-layer FRP plate anchorage device, and is suitable for anchoring a large-tonnage FRP plate cable; the upper clamping plate 6, the lower clamping plate 7, the clamping pieces 8 and the FRP plate 9 all have the same variable curvature waveform, so that the stress distribution in the anchorage device can be effectively improved, the stress concentration of a loading end of the anchorage device is reduced, the anchoring length is shortened, the anchoring efficiency is improved, and the advantage of high tensile strength of the FRP plate 9 is fully exerted.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. The variable-curvature clamping type anchorage device is characterized by comprising an upper clamping plate and a lower clamping plate which are sequentially arranged, wherein a single-layer FRP plate is clamped between the upper clamping plate and the lower clamping plate, both the upper clamping plate and the lower clamping plate are provided with variable-curvature waveforms, the FRP plate is bent into the variable-curvature waveforms, and the variable-curvature waveforms are provided with adjustable waveforms and wave crests.
2. The variable curvature clamping anchor suitable for FRP plates as claimed in claim 1, further comprising an upper ear plate, a lower ear plate and a clamping piece, wherein a plurality of layers of clamping pieces are arranged between the upper clamping plate and the lower clamping plate, the clamping pieces have a variable curvature waveform, and FRP plates are clamped at each layer of a multi-layer structure formed by the upper clamping plate, the plurality of layers of clamping pieces and the lower clamping plate.
3. The variable curvature clamping anchor suitable for FRP plates as claimed in claim 2, wherein the variable curvature wave function of the upper clamping plate, the lower clamping plate and the clamping piece satisfies the condition: the derivative is continuously conducted in the anchorage device, the first derivative and the second derivative are both 0 at the anchorage device outlet, and the first derivative is 0 at the anchorage device inlet.
4. A variable curvature clamping anchor suitable for FRP panels as claimed in claim 2, wherein the upper clamping plate, the lower clamping plate, the clamping plates and the FRP panels have the same waveform in the anchor, and do not bend at the outlet of the anchor, and the bending degree of each wave band gradually increases with the distance from the outlet of the anchor, and is tangential to the longitudinal direction of the FRP panels at the inlet of the anchor.
5. A variable curvature clamping anchor suitable for FRP panels as claimed in claim 1, wherein the function of the variable curvature waveform is:
Figure 276564DEST_PATH_IMAGE001
in the formula (I), the compound is shown in the specification,
Figure 787355DEST_PATH_IMAGE002
,
Figure 707907DEST_PATH_IMAGE003
is the distance from the coordinate center along the longitudinal direction of the FRP plate, and L is the anchoring length, then
Figure 788995DEST_PATH_IMAGE004
;
Figure 935943DEST_PATH_IMAGE005
As the abscissa
Figure 760679DEST_PATH_IMAGE006
The corresponding amplitude value;
Figure 37202DEST_PATH_IMAGE007
in order to control four main parameters of the waveform, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3.
6. The variable curvature clamping anchor for FRP plates as claimed in claim 1 further comprising a washer, a bolt passing through the upper ear plate, the upper clamping plate, the clamping piece, the lower clamping plate and the lower ear plate, and a nut screwed onto the bolt.
7. A variable curvature clamping anchor for FRP plates as claimed in claim 6 wherein bolt holes are provided in the upper ear plate, the upper clamping plate, the lower clamping plate and the lower ear plate through which the bolts pass.
8. The variable curvature clamping type anchorage suitable for FRP plates as claimed in claim 6, wherein the pretightening force applied to the bolt by the nut is gradually increased from the anchorage outlet to the anchorage inlet, and the pretightening force increase value of each stage is 10-20 kN.
9. The variable curvature clamping anchor for FRP plates as claimed in claim 2, wherein in the plurality of FRP plates, the top and bottom FRP plates are respectively tightly jointed with the upper and lower clamping plates, and the middle FRP plate is tightly jointed with the clamping plate.
10. A method for designing a variable curvature clamping anchor suitable for an FRP plate, which is used for designing the variable curvature clamping anchor suitable for the FRP plate as claimed in any one of claims 1 to 9, and comprises the following steps:
setting the outlet of the anchorage device as a coordinate center (0, 0), and designing the variable curvature waveform function, wherein the function is as follows:
Figure 961296DEST_PATH_IMAGE008
in the formula (I), the compound is shown in the specification,
Figure 657857DEST_PATH_IMAGE002
,
Figure 83022DEST_PATH_IMAGE003
is the distance from the coordinate center along the longitudinal direction of the FRP plate, and L is the anchoring length, then
Figure 181428DEST_PATH_IMAGE004
;
Figure 10843DEST_PATH_IMAGE005
As the abscissa
Figure 758482DEST_PATH_IMAGE006
The corresponding amplitude value;
Figure 925021DEST_PATH_IMAGE007
in order to control four main parameters of the waveform, A is the number of positive number adjustable waveforms, w is the number of positive number adjustable wave crests, m and n are positive integers, and m is more than or equal to 3; obtaining the best A, m, n,Combining w parameters to obtain the variable curvature waveform;
processing an upper clamping plate, a lower clamping plate and a clamping piece according to the variable curvature waveform function;
placing the lower clamping plate on the lower lug plate, gradually superposing a layer of FRP plate and a layer of clamping plate to a required number of layers, placing the upper clamping plate on the top FRP plate, and placing the upper lug plate on the upper clamping plate;
placing gaskets at bolt holes at the top of the upper ear plate and the bottom of the lower ear plate, wherein bolts sequentially penetrate through the gaskets, the upper ear plate, the upper clamping plate, the clamping pieces, the lower clamping plate and the lower ear plate;
and tightening the nut to apply variable pre-tightening force to the bolt, bending the FRP plate into a variable-curvature waveform in the anchorage device, and tightly clamping the FRP plate.
CN202210267288.3A 2022-03-18 2022-03-18 Variable-curvature clamping type anchorage device suitable for FRP (fiber reinforced plastic) plate and design method Pending CN114370013A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102094536A (en) * 2011-02-28 2011-06-15 卓清 Array type waved tooth clamp anchor
CN203270946U (en) * 2013-05-31 2013-11-06 南京海拓复合材料有限责任公司 Clamp anchor for protecting soft materials and high-strength sheet clamped by clamp anchor
CN104746803A (en) * 2015-04-02 2015-07-01 招商局重庆交通科研设计院有限公司 Carbon fiber plate anchor gear
CN109881842A (en) * 2019-03-08 2019-06-14 北京工业大学 A kind of FRP sheet material change chucking power wave-shaped splint anchor
CN114150581A (en) * 2021-11-27 2022-03-08 北京工业大学 FRP sheet willow leaf-shaped nick splint anchor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102094536A (en) * 2011-02-28 2011-06-15 卓清 Array type waved tooth clamp anchor
CN203270946U (en) * 2013-05-31 2013-11-06 南京海拓复合材料有限责任公司 Clamp anchor for protecting soft materials and high-strength sheet clamped by clamp anchor
CN104746803A (en) * 2015-04-02 2015-07-01 招商局重庆交通科研设计院有限公司 Carbon fiber plate anchor gear
CN109881842A (en) * 2019-03-08 2019-06-14 北京工业大学 A kind of FRP sheet material change chucking power wave-shaped splint anchor
CN114150581A (en) * 2021-11-27 2022-03-08 北京工业大学 FRP sheet willow leaf-shaped nick splint anchor

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